With the rapid development of technologies, touch screen panels have become popular in people's life. At present, depending on their structure, touch panels can be classified into add-on mode touch panels, on-cell touch panels, in-cell touch panels and so on. An add-on mode touch panel includes a touch panel and a display screen such as a liquid crystal display (LCD) panel that are manufactured separately and then attached together to form the touch screen panel with touch function. Disadvantages of add-on mode touch panels include high manufacturing costs, low light transmission ratio and great module thickness. For an in-cell touch panel, the touch electrodes of the touch panel are embedded inside the liquid crystal display for example, which can reduce the overall thickness of modules and significantly lower manufacturing costs of the touch panels, hence attracting interests of panel manufacturers.
At present, a traditional capacitive in-cell touch panel is implemented by further adding touch driving lines and touch sensing lines directly on an existing thin film field effect transistor (TFT) array substrate, that is, two layers of transparent conducting electrodes (typically strip-like ITO electrodes) intersecting in different planes are manufactured on a surface of the TFT array substrate. These two layers of ITO (indium tin metal oxide) electrodes function as touch driving lines and touch sensing lines of the touch panel respectively and generate inductive capacitance at different-plane intersections of the two ITO electrodes. The operation of this capacitive in-cell touch panel is as follows. When the ITO electrodes functioning as touch driving lines are applied with a touch driving signal, a voltage signal that is coupled out via the inductive capacitance by the touch sensing lines is detected. If a user touches the touch panel during this period, the electric field of the human body acts on the inductive capacitance, causing the capacitance value thereof to change, and thus the voltage signal coupled out by the touch sensing lines is changed. It is possible to determine the positions of contacts depending on the sensed change of the voltage signal.
As for the above-mentioned structure design of the capacitive in-cell touch panel, it is necessary to add a new layer structure on the traditional TFT array substrate, which requires an additional new process in manufacturing TFT array substrate, increasing the production costs and is disadvantageous for improving production efficiency.